The invention relates to an electric furnace, such as an electric arc furnace or a plasma melting furnace, comprising a lifting structure actuating a furnace cover and including a stationary supporting post, a lifting means arranged within the stationary supporting post and a lifting column axially displaceably guided on the stationary supporting post by means of an upper and a lower bearing, which lifting column is liftable and lowerable by the lifting means and engageable with, and disengageable from, the furnace cover.
An electric furnace of this kind is known from U.S.S.R. Pat. No. 287,055. The lifting means in that electric furnace is arranged below the lifting column. Because the two bearings guiding the lifting column have to be as far remote from each other as possible for a perfect accommodation of the cover forces and the moments caused by these forces, a large construction height is necessary with that structure, due to the resulting great length of the lifting column and of the lifting means arranged below the same.
On account of the large construction height, that structure, in addition, is heavy and expensive, pivoting of the cover being effected in an unstable and resilient manner, respectively.